GM's MPG display: Grassroots Motorsports forum: Grassroots Motorsports Magazine

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July 30, 2008 9:50 a.m. Jack SuperDork

My "new to me" 06 Malibu has an average MPG display, but I've been unable to find out how how long a time period it averages. It seems like it might take the last 100 or so miles, but that's just my guess from watching it over the past 5,000 miles.

Does anyone know what time/distance is used for the basis of the average MPG calculation?

Thanks in advance,

jack

EDIT: I realize I can reset it by pushing a button. My question is does it just keep averaging until the button is pressed again, or is there an interval, say the last 1,000 or 2,000 miles, over which it averages, if the button is not pressed.
July 30, 2008 9:57 a.m. ZOOMiata Dork

I can reset mine on my Corvette at any time. I think it shows the average MPG since the last reset. For fun, I set it once on my way to the last HPDE that I did (6.7 litres per 100 km -- about 35 mpg) on the way to the event. Then I reset it for the track day -- 47 litres per 100 km!).
July 30, 2008 10:20 a.m. Jack SuperDork

ZooMiata,

I don't believe mine calulates from the last reset because after 1,000 miles or so there would be enough miles to work against, that it would not vary much due to a different style of driving, but it does respond to a long, hard, fast climb up a mountain, or a 60 mph cruise control run on a flat highway. I'm pretty confident it's not calculation from the last reset. I could be wrong, but I don't think so.

Data point - My Saab (I seem to recall) stated in the manual that it averaged since the last reset or 1,000 (?) miles.

Yeah, it is interesting to see how high or low I can get it.

Jack
July 30, 2008 10:20 a.m. jrw1621 New Reader

My experience on similar cars is that, yes, you can reset it at any time by holding in the button. Similar to a tripometer.
July 30, 2008 11:11 a.m. fastEddie Dork

I think Jack is asking is it a rolling average (the last XXX miles only) or a fixed average (from the last reset). I would guess based on it being an '06 it is a rolling average but can't help with what that mileage amount may be.
July 30, 2008 11:32 a.m. donalson UltraDork

the 06 ford we had reset with the push of a button... was always fun to reset it before a long HW trip... think my wife managed to pull 36mpg when we moved (all 2ndary roads and maybe 5 stops (signs or lights) beyond that she never touched the brakes... just used the cruise settings
July 30, 2008 7:21 p.m. geoffl New Reader

My Corvette can be reset at anytime as well. I think it calculates from the time it was reset to the current time. Not sure it is 100% accurate though.
July 30, 2008 7:30 p.m. iceracer New Reader

My Liberty indicates fairly constant even when stopped. I have only reset it when refueling or starting on a trip.
July 31, 2008 1:28 a.m. DirtyBird222 Reader

average since reset. most of the gm manuals state that.
July 31, 2008 12:33 p.m. 44Dwarf New Reader

I reset my cobalt every 2-3 fill ups and check the gas receipt and its dead on with the computer.
Aug. 1, 2008 12:00 p.m. Jack SuperDork

DirtyBird222 wrote:

average since reset. most of the gm manuals state that.

DB222 - I'll have to check again, because it it's there, I missed it, although often, like on my 88 Saab, they reset after a certain number of miles too.

44D - Mine checks out amazingly close too, something I find surprising given that they would need to measure the gas volume pretty accurately and most odometers are usually conservative an mph or two.

Thanks,

Jack